What can go wrong with speakers

[nima]

What can go wrong with speakers and how these faults manifest themselves?

 

[CnoEvil]

One problem with old speakers, is that the rubber surround on the Woofer gets dozed and loses its flexibility....this can be heard in bass heavy music, as it can make a sort of flapping noise.

 

[lindsayt]

Rubber surrounds rarely develop faults if they are kept out of direct sunlight. I have 50 year old speakers with two 12" cones per channel with the original rubber surrounds. They show every modern speaker I've auditioned a clean pair of heels when it comes to bass quantity and quality.

Foam surrounds on the other hand perish with age. Even if kept out of sunlight. Cleaning off the old surrounds and gluing on new ones is a job that's not too difficult and takes an hour or two of labour.

If overdrivern / drivern with a lot of clipping the insulation on the voicecoil of speaker drivers can melt from excessive heat, resulting in the voicecoil insulation rubbing on the magnets, which sounds like a horrible scratchy sound on bass transients. A replacement cone / complete driver would be the solution to that problem.

Surrounds can also go saggy over time, resulting in voicecoil rub. Turning the cones by 180 degrees can help with this. Otherwise new surrounds will solve it.

If overdriven / excessive clipping voicecoil wire can burn out - like an old filament light bulb. Voicecoil wire is hair thin. This results in a dead driver.

Dead compression drivers are the easiest to fix as you just fit a new diaphragm (which has the voicecoil as part of it). This is a simple 15 minute job.

For conventional cones and domes a burnt out voicecoil requires a new cone or replacement of the whole driver.

Some types of capacitors (found in the crossovers in passive speakers) can go off over time. Other types seem to stay within spec for decades. The solution to out of spec capacitors is to replace them. How easy this is to do depends on how easily accessible the crossover is and on soldering skills.

Electrostatics are a different kettle of fish.

Ribbon tweeters have a reputation for going out of spec over time.

And then theres the fluid in ferro fluid type tweeters...

It's possible for certain models of speakers to catch fire.

 

[Vladimir]

One problem with old speakers, is that the rubber surround on the Woofer gets dozed and loses its flexibility....this can be heard in bass heavy music, as it can make a sort of flapping noise.

If they have rubber surrounds that's great. Problem is when you buy old speakers with foam surrounds that need replacing every ~5 years. Rubber, paper and cloth surrounds will run for 20 years easy.

Edit: Lindsayt beat me to it. 🙂

 

[CnoEvil]

I should have just said, "Check the surrounds".

 

[nima]

If overdrivern / drivern with a lot of clipping the insulation on the voicecoil of speaker drivers can melt from excessive heat, resulting in the voicecoil insulation rubbing on the magnets, which sounds like a horrible scratchy sound on bass transients. A replacement cone / complete driver would be the solution to that problem...

If overdriven / excessive clipping voicecoil wire can burn out - like an old filament light bulb. Voicecoil wire is hair thin. This results in a dead driver...

Some types of capacitors (found in the crossovers in passive speakers) can go off over time. Other types seem to stay within spec for decades. The solution to out of spec capacitors is to replace them. How easy this is to do depends on how easily accessible the crossover is and on soldering skills.

Dead driver means what? No sound? And in first case scenario if voicecoil melts, that's also something that would be noticed easily?

If there is a fault in crossover element could result in simply speaker not sounding as good as it should - something not so evident as previous 2 options?

 

[Vladimir]

If overdrivern / drivern with a lot of clipping the insulation on the voicecoil of speaker drivers can melt from excessive heat, resulting in the voicecoil insulation rubbing on the magnets, which sounds like a horrible scratchy sound on bass transients. A replacement cone / complete driver would be the solution to that problem...

If overdriven / excessive clipping voicecoil wire can burn out - like an old filament light bulb. Voicecoil wire is hair thin. This results in a dead driver...

Some types of capacitors (found in the crossovers in passive speakers) can go off over time. Other types seem to stay within spec for decades. The solution to out of spec capacitors is to replace them. How easy this is to do depends on how easily accessible the crossover is and on soldering skills.

Dead driver means what? No sound? And in first case scenario if voicecoil melts, that's also something that would be noticed easily?

If there is a fault in crossover element could result in simply speaker not sounding as good as it should - something not so evident as previous 2 options?

Dead driver means that particular driver wont work. Usually the tweeters are burnt by irresponsible owners and can be difficult to tell one is not functioning in a multiway speaker design (especially if your hearing isn't the best at high frequencies). When buying second hand the most important listening test is to put your ear on the tweeters to hear they work.

It's also good to reasearch with 20 y/o + speakers if they have ferro-fluid cooling in the tweeter (and squaker in some cases). If yes, then that usually needs replacing with new f-f, which involves disassembling the driver (or replace it with a new equivalent).

Regarding crossovers, if the capacitors are gone bad they will certanly deteriorate the sound, but you may not notice this considering you have no reference how the 100% functioning speaker sounds. With 20 year old speakers general rule of thumb is to replace all electrolytic capacitors, resolder, refresh connections and clean switches and potentiometers. The differences before and after can be huge.

I had a situation with intermitent sound in a pair of vintage speakers and the solution was soldering the crimped internal wiring, which was the last thing on my mind. In a another speaker from the 90's I had the magnet come loose from the driver basket slightly and I heard rattling and distortion above certain loudness levels. I fixed it with resin since the old factory one failed after 15 years. A lot of detective work involved when buying oldies and especially when they are two decades or more, they have high chance to have some defect(s) even when they look and sound good. The materials alone deteriorate and go out of spec since these are transducers and the tolerances and reliability are different from electronics.

This is why JBL vintage speakers are very popular among vintage lovers. They were really good quality built even by todays standards and can survive abuse and 20+ years of service without going too much out of spec and the company still offers reconing kits and replacement drivers. No other company can match that.

 

[Al ears]

One problem with old speakers, is that the rubber surround on the Woofer gets dozed and loses its flexibility....this can be heard in bass heavy music, as it can make a sort of flapping noise.

If they have rubber surrounds that's great. Problem is when you buy old speakers with foam surrounds that need replacing every ~5 years. Rubber, paper and cloth surrounds will run for 20 years easy.

Edit: Lindsayt beat me to it. 🙂

Not if said speakers are left in a damp garden shed for 4 months over winter and than bought back in to a nice centrally-heated house in February........ as my brother can testify to 🙂

Good job they still manufacture those woofers eh?

 

[lindsayt]

If speakers were left in a damp shed and had paper based cones with rubber surrounds, I'd expect the surrounds to be fine, but the cones to be weakened. Wouldn't do the cabinets much good either.

 

[Al ears]

If speakers were left in a damp shed and had paper based cones with rubber surrounds, I'd expect the surrounds to be fine, but the cones to be weakened. Wouldn't do the cabinets much good either.

In his case the rubber perished and on playing them it split badly...

 

[Vladimir]

If speakers were left in a damp shed and had paper based cones with rubber surrounds, I'd expect the surrounds to be fine, but the cones to be weakened. Wouldn't do the cabinets much good either.

In his case the rubber perished and on playing them it split badly...

Which speakers were those?

 

[Al ears]

If speakers were left in a damp shed and had paper based cones with rubber surrounds, I'd expect the surrounds to be fine, but the cones to be weakened. Wouldn't do the cabinets much good either.

In his case the rubber perished and on playing them it split badly...

Which speakers were those?

They were, and still are after resurrection, Mordaunt Short MS10i Pearls. No paper cones here 🙂